Question: What is the greatest common factor of $28$ and $12$ ? Another way to say this is: $\operatorname{gcf}(28, 12) = {?}$
The greatest common factor is the largest number that is a factor of both $28$ and $12$ The factors of $28$ are $1$ $2$ $4$ $7$ $14$ , and $28$ The factors of $12$ are $1$ $2$ $3$ $4$ $6$ , and $12$ Thus, the greatest common factor of $28$ and $12$ is $4$. $\operatorname{gcf}(28, 12) = 4$